Drillproof cylinder lock



Feb. 26 1924.

N. B. HURD DRILL PROOF CYLINDER LOCK Filed March 19. 1923 I INVE NTOR vATTORNEYS an on the inside of the face plate.

NORMAN B. HURD, OF NEW HARDWARE CORPORATION, OF NEW BRITAIN,CONNECTICUT, A CORPO FJATEON OF CONNECTICUT.

BRITAIN, CONNECTICUT, ASSIGNOR T0 TEE MdER/ICAN DBILLPROO-F CYLINDERLOCK.

Application filed March 19, 1923. Serial Ito. 626,051.

To all whom it may concern:

Be it known that I, NORMAN B. Hum), a citizen of the United States ofAmerica, residing at New Britain, Connecticut, have invented a new anduseful Drillproof Cylinder Look, of which the following is aspecification.

My invention relates to a cylinder lock, and more particularly to aso-called burglar proof or armored look.

It is an object of the invention to provide a cylinder lock with ahardened steel face plate so as to prevent damage to the pin tumblers bydrilling from the front end of the look.

It is a more specific object to provide novel means for holding ahardened steel face plate to a cylinder lock.

In the drawings, which show for illustrative purposes only, a preferredform of my invention,

Fig. 1 is a longitudinal central sectional view through a cylinder lockembodying features of my invention.

Fig. 2 is a perspective view of the lock shown in Fig. 1, parts beingrelatively displaced to illustrate the invention.

Fig. 3 is a fragmentary sectional view of a detail.

In said drawings, 5 designates a cylinder constituting part of aso-called cylinder lock. As is usual in looks of this character, a plug6 is rotatably mounted therein and the pin tumblers lying in passages inthe cylinder and plug serve to lock the cylinder and plug againstrelative rotation until moved by the key 7 to the positions shown inFig. 1. In the particular form shown, the plug 6 is provided with aflanged head 8, fitting into a recess in the front of the cylinder 5 andprojecting slightly above the surface thereof.

9 designates an armor or face plate preferably of hardened steel. Thisface plate, which is preferably of substantially the same diameter asthe cylinder 5, is provided with a peripheral flange 10 at the base ofwhich there is an in-turned continuous lip 11, leaving a continuousannular recess 12 The front end of the cylinder 5 is shouldered as at 13for receiving the bottom of the flange 10 and lip 11 and forming a seattherefor.

A plurality of holding devices such as the pins 1PM are provided, and inthe form shown extend longitudinally through passages in the cylinder 5.Each of these pins is provided with a head 15 which in the annularrecess 12, and bears against the lip 11. When the pins 1a are riveted orotherwise secured to the cylinder as indicated at 16 in Fig. 1, the faceplate 9 will be securely held against removal from the cylinder 5 butwill be permitted to rotate relatively to said cylinder, this rotationof course being permitted by reason of the continuous annular recess 12in the face plate. The plug 6 and face plate 9 are each provided withregistering key slots 17--18 respectively, and in the preferred form theplug and face shown at 192O respectively. This cupping serves to holdthe face plate and plug against any substantial relative rotation, andinsures continuous registration of the key slots in the two members.

It will be seen that when the proper key is inserted through the keyslots, the pin tumblers will be moved to their proper positions and theplug may then be rotated by means of the key. lhe face plate 9 will berotated with the plug, this rotation, as before stated, being permittedby reason of the continuous annular recess 12 in which the heads 15 fit.

Since the front faces of the cylinder and plug are covered by the armoror hardened steel face plate, and the securing pins are entirely coveredby the face plate, it will be impossible to remove the armor while thelock is in place and it will be impossible to destroy the tumblers bydrilling from the front end.

While I have disclosed a preferred form of my invention, 1 wish itunderstood that changes may be made within the scope of the appendedclaims.

I claim:

1. In a cylind r look, a cylinder, a plug rotatable therein, a hardenedsteel face plate for said cylinder and plug and rotatably secured tosaid cylinder and rotatable with said plug, said plug and said faceplate having registering key slots therein, and means to hold said faceplate and plug against independent rotation relatively to each other toinsure continuous registration of the key slots in said members,

plate are each cupped as is received v 2. In a cylinder look, acylinder, a plug therein, a hardened steel face plate for said cylinderand plug, said face plate having a peripheral flange and continuousin-turned lip thereon, and a plurality of devices secured to saidcylinder and having flanges overstanding said iii-turned lip forsecuring the face plate on the cylinder, said inturned lip and securingflanges permitting rotation of said face plate on said cylinder; saidplug and cylinder having registering key slots therein.

3. In a cylinder lock, a cylinder, a plug therein, a hardened steel faceplate for said cylinder and plug and completely covering the face ofsaid. cylinder, a plurality of pins secured to said cylinder and havingheads thereon, said face plate having means coacting with the heads ofsaid pins for holding the face plate against movement longitudinally ofsaid cylinder but permitting relative rotationbetween said face plateand cylinder, said plug and face registeringkey slots therein.

4. In a'cylinder lock, a cylinder, a plug therein, one of said membershaving hirality of pins secured-thereto, a hardened steel face plate forsaid cylinder and plug,

plate having said face plate and said pins having coacting means forholding'said face plate in place over said cylinder and plug, said meanspermitting relative rotation between said face plate andsaid membercarrying said pins, said plug and faceplate having registering key slotstherein.

5. In a cylinder lock, a cylinder having a continuous peripheralshoulder on the front end, a plug in said cylinder, a plurality of pinsextending through and secured to said cylinder, each of said pins havinga head thereon at the front of said cylinder, a hardened steel faceplate of substantially the same diameter as said cylinder and having adepending peripheral flange thereon fittingthe peripheral shoulder onsaid cylinder, said depending flange having a continuous, iii-turned lipthereon leaving a continuous annular recess on the inside of said faceplate for the reception of theheads onvsaid pins, whereby the face plateWillbe 'rotatably secured'to said cylin der byinean's of'said lip andsaid heads, said face plate and plug having registering" key slotstherein.

NORMAN B." nnen

